Cashco P2 Manuel d'utilisateur télécharger pdf (Page 2)

IOM-P2

SECTION IV

IV. STARTUP

SECTION V

V. SHUTDOWN

SECTION III

III. PRINCIPLE OF OPERATION

1. Movement occurs as pressure variations register

on the diaphragm (7.1). The registering pressure

is the outlet, P

, or downstream pressure. The

range spring (15) opposes diaphragm move-

ment. As outlet pressure drops, the range spring

push es the diaphragm down, opening the port; as

outlet pres sure in creas es, the diaphragm push es

up and the port opening clos es.

2. A complete diaphragm failure will cause the reg u-

la tor to fail open.

The maximum outlet pressure is stamped on the body

as the upper range spring pres sure level, and is the

rec om mend ed “upper operative limit” for the sens ing

diaphragm (see Sec tion IV. Startup, Step 7). Higher

press ures could dam age the di a phragm. (Field hydro-

static tests fre quent ly de stroy di a phragms. DO NOT

HYDRO STATIC TEST THRU AN IN STALLED UNIT; ISO-

LATE FROM TEST.)

1. Start with the block valves closed. A by pass

valve may be used to maintain out let pres sure

in the down stream sys tem without changing the

fol low ing steps.

2. Relax the range spring (15) by turning knob (4)

counter clockwise (CCW) until ro ta tion comes to

a complete stop.

3. If it is a “hot” piping system, and equipped with

a bypass valve, slowly open the bypass valve

to preheat the system piping and to allow slow

ex pan sion of the piping. Closely monitor outlet

(down stream) pres sure via gauge to ensure not

over-pressurizing. NOTE: If no bypass valve is

in stalled, extra caution should be used in starting

up a cold system; i.e. do everything slowly.

4. Crack open the outlet (downstream) block

valve.

5. Slowly open the inlet (upstream) block valve ob-

serv ing the outlet (downstream) pressure gauge.

De ter mine if the regulator is ﬂ owing. If not, slowly

rotate knob (4) clock wise (CW) until ﬂ ow begins.

6. Continue to slowly open the inlet (upstream) block

valve until fully open.

7. Continue to slowly open the outlet (downstream)

block valve, especially when the downstream pip-

ing system isn't pressurized. If the outlet (down-

stream) pressure exceeds the desired pres sure,

close the block valve and go to Step 2, then return

to Step 4.

8. When ﬂ ow is established steady enough that the

outlet (downstream) block valve is fully open, be-

gin to slowly close the bypass valve if installed.

9. Develop system ﬂ ow to a level near its expected

normal rate, and reset the regulator set point by

turning knob (4) CW to increase outlet pressure,

or CCW to reduce outlet pressure.

10. Reduce system ﬂ ow to a minimum level and ob-

serve set point. Outlet pressure will rise from the

set point of Step 9. The maximum rise in outlet

pressure on decreasing ﬂ ow should not exceed

the stated up per limit of the range spring by greater

than 10%. Example: with 2-100 psig (.14-6.9 Barg)

range spring at low ﬂ ow the outlet pressure should

not exceed 110 psig (7.6 Barg), if it does, con sult

factory.

1. On systems with a bypass valve, and where sys-

tem pressure is to be main tained as the reg u la tor

is shut down, slowly open the bypass valve while

closing the inlet (up stream) block valve. Fully

close the inlet (up stream) block valve. (When on

bypass, the sys tem pres sure must be con stant ly

observed and man u al ly reg u

lat ed. Close the

outlet (down stream) block valve.

2. If the regulator and system are to both be shut

down, slowly close the inlet (upstream) block

valve. Close the outlet (downstream) valve only

if reg u la tor re mov al is required.

CAUTION

Do not walk away and leave a bypassed

regulator unattended.

CAUTION

1 2 3 4 5 6 7 8

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Cashco P2 Manuel d'utilisateur Page 2

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